Prof. Dr. Jiangfeng Du and Prof. Dr. Fazhan Shi Team of the Chinese Academy of Sciences (CAS) Key Laboratory of Microscopic Magnetic Resonance, in collaboration with Dr. Xiaodong Wu of the University of Iowa, US, have made new progress in quantum precision measurement of the diamond nitrogen-vacancy (NV) center system. Using a deep-learning neural network approach, the two-dimensional nanoscale NMR spectra based on diamond quantum precision measurement were accelerated and the detection efficiency was improved by nearly an order of magnitude.
The research results, entitled "Artificial intelligence enhanced two-dimensional nanoscale nuclear magnetic resonance spectroscopy" were published in the September 2020 issue of npj Quantum Information [npj Quantum Information 6, 79 (2020)].
The analysis of molecular structures of substances is an important tool for studying the properties and functions of substances in chemistry and life sciences. Nuclear magnetic resonance (NMR) is widely used in structural biology and clinical medicine because of its advantages such as non-destructive, physiological conditions, and even in situ detection. Traditional NMR techniques are limited by signal collection methods and can only measure the collective signals generated by more than billions of molecular systems. In recent years, nanomagnetic resonance spectroscopy has been realized based on diamond NV center.
The CAS Key Laboratory of Microscopic Magnetic Resonance has achieved the first nanoscale two-dimensional NMR spectrum with a pair of coupled carbon-13 nuclear spins in the direction of NV color center-based nanoscale NMR on the optical detection magnetic resonance (ODMR) experimental platform [published in Adv. Quantum Technol. 2020, 3, 1900136 (2020)]. Due to the extremely weak microscopic NMR signals, it often takes a long time (hours to days) to accumulate signals in experiments for nanoscale 2D NMR spectroscopy measurements in order to obtain a high signal-to-noise ratio. To improve the detection efficiency, the research team led by Prof. Dr. Jiangfeng Du applied artificial intelligence methods to the data processing and analysis of 2D NMR spectra by training deep learning neural networks with model data and combining them with matrix filling methods, which finally made it possible to obtain nearly 4-fold (~5.7 dB) signal-to-noise ratio improvement even with a time consumption of 10%.
Two-dimensional spectroscopy is the key to spin distance resolution and the basis of single-molecule structure resolution. This work provides a universal method applicable to the acceleration of two-dimensional NMR spectroscopy, which can be applied to the structure resolution of single molecules at the nanoscale.
Fig. (a) After adopting the deep learning algorithm, it is possible to extract complex nanomagnetic spectral line information from a small amount of information, thus greatly improving the efficiency of experimental measurements. Figure (b) Deep learning combined with matrix padding algorithm can remove bias while maintaining reconstruction capability.
CIQTEK developed and manufactured the quantum diamond single spin spectroscopy based on optical detection magnetic resonance technology. Using the NV center-based quantum precision measurement technology, it can also realize nano-NMR and carry out experimental research work related to nano-scale 2D NMR spectroscopy measurements. This spectrometer is stable and powerful and will help researchers to complete their research more conveniently.
The quantum diamond single spin spectroscopy is a quantum experimental platform based on the principle of spin magnetic resonance in the NV center. By controlling the basic physical quantities such as light, electricity, and magnetism, quantum manipulation and readout of the spins of the luminescent defects in the diamond NV center are realized. Compared with traditional paramagnetic resonance and nuclear magnetic resonance, it has the unique advantages of the quantum pure initial state, long spin-quantum coherence time, powerful quantum manipulation ability, and intuitive quantum collapse measurement experimental results.
The quantum diamond single spin spectroscopy has unique advantages in applications such as spectroscopic analysis and structure resolution, which can realize single protein and other single molecule electrons paramagnetic resonance, nano-scale nuclear magnetic resonance, temperature, magnetic field, and action potential detection in living cells.